I have a 1967 580CK with the diesel engine. Bought it a couple of years ago. The backhoe boom has had a bit of drift since I got it, but it is now to the point where when I raise it, within about a minute, the bucket will be sitting on the ground again. There is also a fair amount of leakage around the control valve area. I need to go in and check fittings to be sure they are tight, however I suspect that there is leakage in the spool (hopefully degraded seals as opposed to metal to metal wear). My question is this: Is it possible to get the spool out of the boom control valve without having to remove the backhoe and pull the entire control valve assembly? I need to do that at some point, but I was hoping to be able to do only the boom control valve right now to get the thing functioning in the short term. It is a pain to use even the front loader right now because I have to reach back and raise the boom every minute or I'll end up dragging a trench from the backhoe bucket. Thanks, Mark
Have you checked the boom cylinder? It's usually much more likely to be piston seals than the valve spool, though that is of course a possibility.
I pulled a few out from the top and replaced O rings and taken a pressure relief valves out of the bottom to replace without taking the hoe apart. Had a boom slowly drift down once and it was something on the bottom of the valve that was loose. As mentioned though odds are it's the piston seals.
Right Billrog, if the cap that holds the centering spring is loose the spool may be centering out of neutral, that should be an easy thing to check/fix.
Not an answer to your question but if you're just using the loader, you can chain the boom up to the loops on each side of the rear of the machine over the stabilizers. If yours doesn't have them, you can weld on a couple grab hooks to hold a piece of chain.
I suppose an easy way to see if its the piston seals is to let it drift down to the ground, then start and apply down pressure to see if there is a delay while the cylinder refills. Like when you drop the arms from mid position with float, there's a delay in getting down pressure.
Mark ......Heres a thread that D26 just posted about a drifting cylinder some good stuff on there and some good pics of tearing down a cylinder on page 14.........Sounds like it probably the cylinder i would check it first but like bilrog says these spools can be pulled out with it on the machine kinda a pita but doable good luck...... HeavyEquipmentForums